[BUG] Claude in Chrome: extension icon opens blank panel instead of resuming active Cowork session

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

During a conversation on the Claude browser extension panel, a click away loses the panel and chat and a subsequent click on the Claude extension icon starts a new conversation instead of resuming the most recent session. There's no back button or way to get back to it.
The session was actually saved and is in the desktop chat history. From the browser, this looks like total data loss.
Opus had been investigating with 7 minutes of network captures, page reloads, downloads and trial results - which all appeared lost.
The desktop chat list had captured this session - something I just discovered and is apparently a Max plan feature??

Related but distinct from #88237 and #83822: in my case the extension connection works and sessions complete successfully; the bug is that the extension icon opens a new blank panel instead of resuming the saved session, which appears intact in desktop/claude.ai history

What Should Happen?

Clicking the Claude extension icon in the browser should resume the active/most recent session, or show a list of recent sessions in the panel, allowing continuation as advertised ("Cowork sessions move with you")

Error Messages/Logs

N/A - no error reported

Steps to Reproduce

• On a Max plan (with Cowork enabled), open the Claude side panel in Chrome via the extension icon.
• Start the session
• While the session runs, click a link, switch tabs or another browser interaction that takes away from the panel
• Click the extension icon again
• The panel opens a new conversation. There is no back button, session list, or indication that the session still exists.
• Go to the Claude desktop app and check the chat list for the saved session.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.234

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_